Changers for optical recording media like CD, DVD, or the like generally consist of a main chassis including the drive elements and the electrical modules for processing the signals for the recording and/or playback operation. Within the chassis a number of trays is arranged one above the other, each tray being capable of holding an optical recording medium. For the playback and/or recording operation, the trays can be moved from a storage position to a playback position. For this purpose, the respective tray holding the recording medium which is to be played back or recorded, is usually grabbed by two hooks engaging with corresponding recesses of the tray, one hook at each side of the tray. Since the hooks have to catch and to release the trays in the storage position, a rotation mechanism is provided for rotating the hooks from their tray transport position to the tray grabbing position. Such a rotation mechanism can, for example, be realised using hooks provided with two studs and cam grooves having a bent part at one end. When the hooks are moved along the cam grooves they are forced into rotation as soon as the first studs arrive at the bent parts of the cam grooves (cf. FIG. 1).
For very compact changers, due to space requirements very often only a single hook is used for tray transport. In this case, however, it can occur that the hook accidentally releases the tray due to vibrations or a canting of the tray. If this happens, the tray has to be moved back into the storage position before it can be grabbed again.
The document JP 08-161813 discloses a changer using a single transport hook, wherein the rotation mechanism is realised using a coil spring and a salient pin. When the hook is moved to the storage position of the tray, part of the hook abuts the salient pin and the hook is rotated into a tray grabbing position. At the same time, the coil spring is strained, forcing the hook back into the tray transport position when the hook is retracted from the storage position of the tray. To prevent that the hook accidentally releases the tray during transport, the hook is provided with a pin contacting a guide shaft during tray transport. This contacting limits any rotation of the hook during tray transport to such an amount that the tray is not released under normal conditions. However, in case of strong vibrations or a canting of the tray, it can still occur that the tray is released during transport. In this case it has to be brought back into the storage position before it can be grabbed again.
It is an object of the invention to improve a known changer with a tray loading mechanism.